- The Food and Drug Administration on Thursday approved a cancer immunotherapy from GlaxoSmithKline for recurrent or advanced endometrial cancers with a specific type of genetic error that disrupts cells' ability to repair DNA.
- The drug, which GSK will sell as Jemperli, is the seventh immunotherapy cleared by the FDA that blocks signaling through either PD-1 or PD-L1 proteins, joining Merck & Co.'s Keytruda, Bristol Myers Squibb's Opdivo and treatments from Roche, Pfizer, AstraZeneca and Regeneron.
- GSK set Jemperli's list price at about $10,400 per 500 mg vial, which is initially given once every three weeks for four doses and then at a larger dose for longer intervals thereafter. The British drugmaker estimates the average monthly wholesale cost to be about $15,000, which is slightly higher than the monthly cost of either Keytruda or Opdivo in other cancers.
The development of PD-1 or PD-L1 targeting immunotherapies has been among the fastest of any drug class, reflecting both rapid clinical progress as well as the influx of large sums of drugmaker dollars.
Like others before it, Jemperli was approved on an accelerated basis, supported by data from a small, single-arm clinical trial that tested the drug in multiple kinds of solid tumors. The study, called GARNET, showed treatment with Jemperli shrank tumors in about 42% of the 71 patients with advanced endometrial cancer.
GSK will have to confirm those results lead to better health outcomes, an area of increased scrutiny of late from regulators. Four accelerated immunotherapy approvals have been withdrawn in recent months, and six others are set to be evaluated next week at an unusual three-day FDA meeting.
Endometrial cancer is the most common gynecological malignancy in the U.S., according to the FDA. About three-quarters of diagnoses are made, however, when tumors are in early stages of growth and can be removed surgically.
All of the trial participants had tumors that were positive for a genetic abnormality known as mismatch-repair deficiency, or dMMR. While less common — the FDA estimates about 25% to 30% of patients with advanced endometrial cancer have dMMR-positive tumors — the genetic error has been associated with high rates of tumor recurrence.
After a median follow-up of about 14 months, the median duration of response to Jemperli had not yet been reached. More than 90% of the trial volunteers whose tumors responded to treatment were still responding six months later, according to GSK.
Jemperli was licensed from Anaptys Bio by the Massachusetts-based cancer biotech Tesaro, which GSK acquired for $5.1 billion in late 2019.
The drug's approval marks GSK's entry into the cancer immunotherapy field. But Jemperli is unlikely to become a top-seller any time soon due to its initial approval's relatively narrow target population and competition from others.
Merck's Keytruda, for instance, is already approved for any dMMR-positive cancer, regardless of tumor type, following chemotherapy. Data supporting that approval also came from a small study, which showed a generally similar response rate.